[PATCH] pci: fix incorrect value returned from pcie_get_speed_cap

[Alex Deucher]

On Wed, Nov 14, 2018 at 10:44 AM Alex Deucher <alexdeucher at gmail.com> wrote:
>
> On Tue, Oct 30, 2018 at 2:00 PM Alex Deucher <alexdeucher at gmail.com> wrote:
> >
> > On Tue, Oct 30, 2018 at 12:36 PM Mikulas Patocka <mpatocka at redhat.com> wrote:
> > >
> > > The macros PCI_EXP_LNKCAP_SLS_*GB are values, not bit masks. We must mask
> > > the register and compare it against them.
> > >
> > > This patch fixes errors "amdgpu: [powerplay] failed to send message 261
> > > ret is 0" errors when PCIe-v3 card is plugged into PCIe-v1 slot, because
> > > the slot is being incorrectly reported as PCIe-v3 capable.
> > >
> > > Signed-off-by: Mikulas Patocka <mpatocka at redhat.com>
> > > Fixes: 6cf57be0f78e ("PCI: Add pcie_get_speed_cap() to find max supported link speed")
> > > Cc: stable at vger.kernel.org      # v4.17+
> >
> > Acked-by: Alex Deucher <alexander.deucher at amd.com>
>
>
> Has this patch been picked up yet?  It fixes a ton of bugs.  Please apply!

Any word on this?  Fixes:
https://bugs.freedesktop.org/show_bug.cgi?id=108704
https://bugs.freedesktop.org/show_bug.cgi?id=108778
and several others.

Alex

>
> Alex
>
> >
> > >
> > > ---
> > >  drivers/pci/pci.c |    8 ++++----
> > >  1 file changed, 4 insertions(+), 4 deletions(-)
> > >
> > > Index: linux-4.19/drivers/pci/pci.c
> > > ===================================================================
> > > --- linux-4.19.orig/drivers/pci/pci.c   2018-10-30 16:58:58.000000000 +0100
> > > +++ linux-4.19/drivers/pci/pci.c        2018-10-30 16:58:58.000000000 +0100
> > > @@ -5492,13 +5492,13 @@ enum pci_bus_speed pcie_get_speed_cap(st
> > >
> > >         pcie_capability_read_dword(dev, PCI_EXP_LNKCAP, &lnkcap);
> > >         if (lnkcap) {
> > > -               if (lnkcap & PCI_EXP_LNKCAP_SLS_16_0GB)
> > > +               if ((lnkcap & PCI_EXP_LNKCAP_SLS) == PCI_EXP_LNKCAP_SLS_16_0GB)
> > >                         return PCIE_SPEED_16_0GT;
> > > -               else if (lnkcap & PCI_EXP_LNKCAP_SLS_8_0GB)
> > > +               else if ((lnkcap & PCI_EXP_LNKCAP_SLS) == PCI_EXP_LNKCAP_SLS_8_0GB)
> > >                         return PCIE_SPEED_8_0GT;
> > > -               else if (lnkcap & PCI_EXP_LNKCAP_SLS_5_0GB)
> > > +               else if ((lnkcap & PCI_EXP_LNKCAP_SLS) ==PCI_EXP_LNKCAP_SLS_5_0GB)
> > >                         return PCIE_SPEED_5_0GT;
> > > -               else if (lnkcap & PCI_EXP_LNKCAP_SLS_2_5GB)
> > > +               else if ((lnkcap & PCI_EXP_LNKCAP_SLS) == PCI_EXP_LNKCAP_SLS_2_5GB)
> > >                         return PCIE_SPEED_2_5GT;
> > >         }
> > >